There are other nodes under that. I haven't talked to the model creator yet, but I think that there is a "front" and "back" for each object in the model. At least that's what it's starting to look like to me. The model is about 13MB, so instead of attaching it here, I've made it available to download here:
http://quasar.unl.edu/all_centered.lwo
Will I have to set a center for each child object or is there a way of treating them as a whole.
Thanks.
Aaron